The present invention relates to an analytical system for detecting an analyte in a body fluid comprising a reusable analyzing instrument and a disposable integrated puncturing and analyzing element. The integrated puncturing and analyzing element has a puncturing element with a tip for generating a puncture wound in a body part and an elongated flat test strip which comprises a top side and a bottom side. The analyzing instrument has a housing, a holder for holding the integrated puncturing and analyzing element, and a coupling unit for coupling the puncturing element to a drive, said drive being adapted for driving a puncturing movement of the puncturing element during which a puncturing element is moved on a movement path, said puncturing movement including a forward phase in which the puncturing element is moved in a puncturing direction and a retraction phase during which the puncturing element is moved, after reaching a reversal point, opposite to the puncturing direction. The puncturing element is arranged parallel to the test strip and is movable on its movement path relative to the test strip.
For diagnostic purposes, small amounts of body fluids, such as blood, are removed from a body part, such as a tip of a finger. Puncturing instruments having lancets or puncturing elements are used for this purpose to generate a wound in a body part. The puncturing systems are provided such that they can be used by the patient or a caregiver.
After generating a puncture wound in the body part using the puncturing system, the body fluid must be applied to a test strip and transferred to an analytical system in a further step. Frequently, this will be a separate analytical system comprising an analyzing instrument and a disposable test strip. The analytical system is then used to detect the analyte of interest in the fluid.
Often, two separate instruments are used according to the state of the art; one as a puncturing instrument for generating the puncture wound, the other as an analyzing instrument for analyzing the body fluid of the puncture wound. The user thus has to operate two different instruments. After generating the puncture wound, he can mechanically squeeze the finger tip in order to increase the exit of blood from the finger. Only then does he touch the analyzing instrument to the puncture wound and take up a drop. This handling is strongly preferred by some users since they have full control over the action involved in blood collection and diagnosis. They are the ones determining how to puncture and how much blood to squeeze from the wound. The user thus willingly accepts, on the one hand, that more blood exits from the wound than absolutely necessary for analysis, and, on the other hand, that the systems get more contaminated.
The users find it advantageous to perform action sequences they trained to do and are familiar with, while having control over the analysis required for diagnosis including the blood collection. The two instruments, the puncturing instrument and the analyzing instrument, can be relatively simple systems which can be manufactured cheaply since each instrument needs to perform exactly only one function.
However, it is disadvantageous that one disposable element needs to be used in each of the systems, namely the lancet or the puncturing element in the puncturing system and the test strip having the analyzing element in the analytical system. Hence, the user is obliged to use and replace, procure and keep in stock two different consumable components. Moreover, the user is obliged to carry two instruments at all times.
For this reason, the state of the art shows that some effort has been made to improve the analysis of body fluids for the user. In the so-called compact instruments, the analyzing instrument and the puncturing instrument are integrated into a single instrument. Although the user has only a single instrument for the analysis, there is still a need to keep two different consumable elements in stock. The mechanical structure of such instruments is fairly complex. In many cases, they are considerably larger than the corresponding individual instruments. The use of cartridges is feasible only in the case of the test strips, but not the lancets. A combined analyzing instrument is described, e.g., in WO 2005/006985 A2.
Aside from this, much effort has been put into improving the analysis of body fluids with fully automatic systems which comprise an integrated puncturing and analyzing element having a test strip and a puncturing element. The exit point of the puncturing element and the reception point for the body fluid exiting a puncture wound are identical in these instruments. The blood, or the body fluid, is transferred from the wound by means of a capillary channel. The user places the instrument on his finger only once and then can read the analytical result directly after a time of analysis has elapsed. All intermediate steps are carried out by the instrument.
Many users do not accept fully automated instruments since they have no influence on the collection of blood and cannot recognize whether or not or how much blood was collected and how it is transported to the analyzing element. They do not wish to relinquish control over the individual operating steps to the system. Moreover, fully automated systems are expensive and complicated to manufacture.